In an online community I used to frequent, there was a majority of Americans and then some people from different European countries, like I'm from Belgium and this one friend, T, was from Country X.
He had already often been annoyed by people who did not know where Country X was or who thought it was a third world country or something.
One day, the following conversation takes place in the chat room:
T: Grrrr my connection broke again, my internet is so sucky!
K: (one of our American members): Aww yeah T., I know where you're coming from!
T: Look K, I'm sick and tired of you bashing my country. Just because my internet connection breaks doesn't mean Country X. is behind on computers or something!
Everyone (except me):
Me: (who knew immediately, due to being foreign myself, that T. had just misunderstood the phrase):
Um, T., K. just meant he knows how you feel, because his own comp breaks down often. That's what "I know where you're coming from" means.
Everyone else: Ah!